We study the quantal dynamics of a harmonically driven quartic double well in the presence of dissipation. A master equation for the reduced density operator is derived in the Floquet representation. In the classical limit, this system corresponds to a Duffing oscillator with Ohmic damping. We present numerical results for the transient time evolution and for the stationary sate. The influence of the weak dissipation on interference effects in the context of driven tunnelling is discussed on the basis of these results. We find that the coherent suppression of tunnelling can be stabilized by reservoir-induced noise for a suitably chosen temperature.We study the quantal dynamics of a harmonically driven quartic double well in the presence of dissipation. A master equation for the reduced density operator is derived in the Floquet representation. In the classical limit, this system corresponds to a Duffing oscillator with Ohmic damping. We present numerical results for the transient time evolution and for the stationary sate. The influence of the weak dissipation on interference effects in the context of driven tunnelling is discussed on the basis of these results. We find that the coherent suppression of tunnelling can be stabilized by reservoir-induced noise for a suitably chosen temperature.

Europhysics Letters (EPL)Apr 1, 199392 citations

Quantum Noise in Mesoscopic Physics

Springer eBooksJan 1, 2003508 citations

Observation of quantum stochastic synchronization in a dissipative quantum system

G. M. Xue, Ming Gong, Huikai Xu +8 more

We report the observation of quantum stochastic synchronization (QSS) in a dissipative quantum system---a moderately damped current-biased Josephson junction. We show that when the junction is biased subcritically by a combination of a constant current and a small sinusoidal modulation signal, forced phase synchronization between the otherwise random, incoherent quantum tunneling and the signal may arise as a consequence of the interplay between quantum fluctuation and the weak periodic drive. It is found that optimal synchronization occurs at a signal frequency ${f}_{\text{QSS}}$ that is comparable to the quantum tunneling rate. We also find a phenomenon called ``modulation induced suppression of quantum noise'': for signal frequency well below ${f}_{\text{QSS}},$ the power spectral density of escape time distribution of the junction could be reduced substantially from the floor level of the unmodulated system. Furthermore, we demonstrate that the application of a small signal with proper phase can suppress the average tunneling rate and enhance the stability of the metastable system. Our experimental results agree well with the numerical calculations without the use of adjustable parameters.We report the observation of quantum stochastic synchronization (QSS) in a dissipative quantum system---a moderately damped current-biased Josephson junction. We show that when the junction is biased subcritically by a combination of a constant current and a small sinusoidal modulation signal, forced phase synchronization between the otherwise random, incoherent quantum tunneling and the signal may arise as a consequence of the interplay between quantum fluctuation and the weak periodic drive. It is found that optimal synchronization occurs at a signal frequency ${f}_{\text{QSS}}$ that is comparable to the quantum tunneling rate. We also find a phenomenon called ``modulation induced suppression of quantum noise'': for signal frequency well below ${f}_{\text{QSS}},$ the power spectral density of escape time distribution of the junction could be reduced substantially from the floor level of the unmodulated system. Furthermore, we demonstrate that the application of a small signal with proper phase can suppress the average tunneling rate and enhance the stability of the metastable system. Our experimental results agree well with the numerical calculations without the use of adjustable parameters.

Physical Review BDec 3, 201411 citations

Quantum noise reduction in coupled oscillators

B. Baseia, A.L Silva, Cristian Bonato

Brazilian Journal of PhysicsJan 1, 19930 citations

Noise suppression in three-level atomic system driven by quantized field

A. Gelman, V. Mironov

Numerically by the Monte-Carlo wave function (MCWF) method and analytically by the Heisenberg-Langevin method the interaction of three-level atom with quantized electromagnetic field is investigated in the conditions of electromagnetically induced transparency (EIT) conditions. A possibility of noise suppression in atomic system by means of quantum features of squeezed light is examined in detail. The characteristics of atomic system responsible for relaxation processes and noise in EIT are found.Numerically by the Monte-Carlo wave function (MCWF) method and analytically by the Heisenberg-Langevin method the interaction of three-level atom with quantized electromagnetic field is investigated in the conditions of electromagnetically induced transparency (EIT) conditions. A possibility of noise suppression in atomic system by means of quantum features of squeezed light is examined in detail. The characteristics of atomic system responsible for relaxation processes and noise in EIT are found.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIEOct 23, 20090 citations

{f}_{\text{QSS}}

that is comparable to the quantum tunneling rate. We also find a phenomenon called ``modulation induced suppression of quantum noise'': for signal frequency well below

{f}_{\text{QSS}},

the power spectral density of escape time distribution of the junction could be reduced substantially from the floor level of the unmodulated system. Furthermore, we demonstrate that the application of a small signal with proper phase can suppress the average tunneling rate and enhance the stability of the metastable system. Our experimental results agree well with the numerical calculations without the use of adjustable parameters.